Hello James, Jeff, Tony, I considered the Arduino and the ATMEGA32 but I needed a lot of I/O and I don't need CPP or Analog. Yes, there is more support for the Arduino but there is a lot out there for the PIC. I could use some more I/O pins. I am using shift registers to control the address lines going to the programming socket and a 8 to 3 encoder chip for the interrupts. The FTDI chip that I am considering is a FT232RL. It will be connected to the PIC in a direct manner and only the USB side will be able to connect to a PC. I know that the RS232 port on the PIC swings 0 to 5 volts. I'll have to check the datasheet for the FT232RL to see if it swings 0 to 3.3 or 5 volts. I don't know. I use C to do my coding. I understand Assembly to a certain point. I am able to follow along the code and see what is going on but I have a difficult time creating my own Assembly programs. I am going to run the 4520 at 40MHz so speed isn't going to be a big issue for the programmer. Right now I am using relays to switch the Address lines and various programming voltages to the appropriate pins on the programming socket. I found a program for controlling a LCD on the MC website. The only problem is that I can't find where that Data Pins are being defined. I found the definitions for the control lines. Thanks, rich! On 11/14/2017 3:18 PM, James Cameron wrote: > Thanks for the STM32 Blue Pill reference. An interesting looking board. > > On Tue, Nov 14, 2017 at 03:04:26PM +0000, Clint Jay wrote: >> Jeff, you raise good points but I would prefer to be safe than sorry, >> designing/building and coding for the MAX232 or other serial driver will >> ensure compatibility (as far as RS-232 is able to be compatible) with th= e >> widest range of PCs and prevent anything 'unpleasant' happening if the >> device is plugged into an unknown machine. >> >> As heretical as it would seem I'd have to admit you may have a point abo= ut >> Arduino, it's a known hardware platform that is proven to work. >> >> Similarly, I've been exploring options with STM32 Blue Pill boards recen= tly >> but I still like and write code for PIC devices, as and when I need extr= a >> horsepower I may well leave the PIC Path and move to ARM, they're *so* >> cheap and have an abundance of facilities. >> >> >> >> On 14 November 2017 at 14:54, Byron Jeff wrote: >> >>> Tony, >>> >>> There are actually two types of FTDI serial ports. There is the RS232 o= ne >>> with a DB9 connector on the end. Typically that port will signal betwee= n >>> +/- 7 volts or so. Then there are the small FTDI TTL serial adapters. >>> Depending on configuration they will swing either between 0 and 5 volts= or >>> 0 and 3.3 volts. >>> >>> In today's serial PC world rarely does an actual MAX232 need to be used= for >>> level translation. Even with actual RS232 ports, virtually all of them >>> signal properly with a 0/5V TTL signal. Note that the sign is inverted = such >>> that a logical 1 is represented by 0V and a zero by 5V. >>> >>> For years I've used a simple voltage clamp to limit the swings. The bas= ic >>> circuit is here: https://i.stack.imgur.com/jyZvD.gif D1 conducts when V= in >>> is above VMax and D2 conducts then Vin is below Vmin. R limits the curr= ent. >>> I typically put a second resistor after the clamp. I find that 1K for b= oth >>> works well with PIC inputs. >>> >>> A couple of variations are helpful. If D1 and D2 are Schotty diodes the= n >>> the voltage overshoot is typically only 0.3V or so. Also if D2 is a Zen= er >>> then D1 is unnecessary because the Zener action will limit the high vol= tage >>> while normal conduction clamps the low voltage. >>> >>> With the signal inverted there are a few things you can do to manage it= .. >>> I've been using PIC24FV parts for several years. The hardware EUARTS on >>> them can be inverted in software. It is also possible to bit bang a dig= ital >>> input/output for serial. Otherwise a NPN transistor whose base is conne= cted >>> to Vout, emitter grounded, and a pullup collector will invert the signa= l in >>> hardware. >>> >>> Another thought that may be traitorous on this board: ever considered a= n >>> Arduino? Complete boards with the USB serial adapter on board clock in = at >>> about $5 USD. Boards like a Nano will plug right into a breadboard. Plu= g in >>> a USB cable, load the Arduino IDE and you're going literally in about 5 >>> minutes. Tons of libraries already built into the platform. >>> >>> As I've progressed in the hobby, I find that sometimes it's just more >>> trouble than it's worth to try to roll everything from scratch. Back in= the >>> PIC 16C54 days, the price and functionality was a compelling reason to >>> switch as compared to the alternatives. But in 2017 with high level boa= rds >>> such as a Raspberry PI Zero W that runs Linux and having a complete >>> wireles setup >>> for less than $10 USD and Arduino clones literally running 5 for $20, i= t >>> becomes more difficult to justify wiring up a board from scratch and >>> programming in assembly anymore. Those who have never done it may need = the >>> experience. But those of us who have a closetfull of t-shirts with >>> 'Assembly coder' emblazoned upon them? Not so much. I find now that I s= pend >>> more time and energy trying to match the hardware/firmware to the >>> application. It literally may be more adventageous to throw a RasPi Zer= oW >>> into a problem to make a wireless remote light switch than any alternat= ive >>> for >>> example. >>> >>> BAJ >>> >>> On Wed, Nov 15, 2017 at 12:54:26AM +1100, Anthony Nixon wrote: >>>> You wont need a level translator with the FTDI chip. It will directly >>>> interface to the PIC, and the FTDI directly interfaces to the USB port >>>> with the right support components which are just a handful of >>>> passives. >>>> >>>> The trick is whether or not the FTDI will be powered by the USB port >>>> or by the PIC circuit. >>>> >>>> cheers >>>> >>>> Tony >>>> >>>> On Tue, Nov 14, 2017 at 11:56 PM, Richard Pope >>> wrote: >>>>> Clint, >>>>> I'll do that this evening after I get up. I appreciate the insi= ght >>>>> and help! I will probably have to use a MAX232 to do the level >>>>> translation. I appreciate you reminding me of that. >>>>> Thanks, >>>>> rich! >>>>> >>>>> On 11/14/2017 6:47 AM, Clint Jay wrote: >>>>>> There may be, I've usually just rolled my own routines to service th= e >>>>>> EUSART though I haven't used the '4520 specifically. >>>>>> >>>>>> I don't think there are huge differences between most EUSART >>> enabled mid >>>>>> range devices so there should be plenty of example code to examine a= nd >>>>>> modify for your needs. >>>>>> >>>>>> You'll need a level translator if you're going PIC to PC directly. >>>>>> >>>>>> On 14 Nov 2017 12:36, "Richard Pope" wrote: >>>>>> >>>>>>> Clint, >>>>>>> Yes, I am using a FTDI to RS232 converter to hook the PC to = the >>>>>>> PIC. I just found out that all that I need to do is treat the >>> connection >>>>>>> to the PIC as a Serial connection. Is there a MC Serial Library >>>>>>> available? I'm the one that was confused. >>>>>>> Thanks, >>>>>>> rich! >>>>>>> >>>>>>> On 11/14/2017 6:28 AM, Clint Jay wrote: >>>>>>>> I'm a little confused but the way I read your message would sugges= t >>> that >>>>>>>> you're going to connect your PIC to the PC with an FTDI USB to >>> serial >>>>>>>> device? >>>>>>>> >>>>>>>> Or have I misunderstood and you're hoping to connect the PIC to th= e >>> FTDI >>>>>>>> with USB? >>>>>>>> >>>>>>>> On 14 Nov 2017 12:25, "Richard Pope" >>> wrote: >>>>>>>> HELLO ALL, >>>>>>>> . . . . I could really use some help with using USB on the PIC >>> 18F4520. >>>>>>>> I am going to use a FTDI USB to RS232 converter to talk to the PIC >>>>>>>> 18F4520 Through the RX and TX Pins. I want to send Configuration >>> Code to >>>>>>>> a 24C512 serial EPROM. When I add additional devices I want to be >>> able >>>>>>>> to update the EPROM. I also want to be able to use a Win 8.1 64bit >>> Pro >>>>>>>> PC to control the Programmer. I also do a lot of searching and >>> research >>>>>>>> on materials that I acquire from the MicroChip website. I have bee= n >>>>>>>> reading the MC USB Device Firmware Framework User's Guide. >>>>>>>> . . . . I have the latest version of MpLab, and the latest >>> versions of >>>>>>>> the X8, X18, and X32 Compilers installed. I also see that I need t= o >>>>>>>> install the latest versions of C30 C and C18 C Compilers and setup >>> the >>>>>>>> proper Paths for these files. I don't mind doing the footwork. I a= m >>>>>>>> Disabled and retired. This gives me a lot of free time. >>>>>>>> Thanks, >>>>>>>> >>>>>>>> Richard R. Pope >>>>>>>> 1230 19th Street #5 >>>>>>>> Reedsburg, WI 53959, USA >>>>>>>> 1-608-768-7448 >>>>>>>> mechanic_2@charter.net >>>>>>>> >>>>>>>> >>>>>>>> --- >>>>>>>> This email has been checked for viruses by Avast antivirus softwar= e. >>>>>>>> https://www.avast.com/antivirus >>>>>>>> >>>>>>>> -- >>>>>>>> http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive >>>>>>>> View/change your membership options at >>>>>>>> http://mailman.mit.edu/mailman/listinfo/piclist >>>>>>> -- >>>>>>> http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive >>>>>>> View/change your membership options at >>>>>>> http://mailman.mit.edu/mailman/listinfo/piclist >>>>>>> >>>>> -- >>>>> http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive >>>>> View/change your membership options at >>>>> http://mailman.mit.edu/mailman/listinfo/piclist >>>> -- >>>> http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive >>>> View/change your membership options at >>>> http://mailman.mit.edu/mailman/listinfo/piclist >>> -- >>> Byron A. Jeff >>> Associate Professor: Department of Computer Science and Information >>> Technology >>> College of Information and Mathematical Sciences >>> Clayton State University >>> http://faculty.clayton.edu/bjeff >>> -- >>> http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive >>> View/change your membership options at >>> http://mailman.mit.edu/mailman/listinfo/piclist >>> >> >> >> -- >> Clint. >> >> *No trees were harmed in the sending of this mail. However, a large numb= er >> of electrons were greatly inconvenienced.* >> -- >> http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive >> View/change your membership options at >> http://mailman.mit.edu/mailman/listinfo/piclist -- http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .